A medium-sized solar flare erupted from the sun in an impressive display captured by NASA cameras aboard an orbiting satellite called the Solar Dynamics Observatory. NASA says the flare peaked Tuesday and created a large cloud that appeared to cover almost half the surface of the sun. NASA/SDO/AP

Armed Yemeni tribesmen take positions on a roadside in Taiz, Yemen. Hundreds of armed tribesmen have taken control of part of Yemen's second-largest city. The advance on Taiz showed the government's already tenuous control over the country has slipped further since President Ali Abdullah Saleh left for medical care in neighboring Saudi Arabia. Anees Mahyoub/AP

Children practice during a ballet class at the Croatian National Theatre in the Adriatic port of Split. Matko Biljak/Reuters

Elephants feast on cucumbers in Emmen, Netherlands. The cucumbers were donated by a farmer who could not sell his produce because cucumbers were initially blamed for the deadly outbreak of E. coli infections. Tests have since ruled out cucumbers as the source of contamination. Dierenpark Emmen/Wijbren Landman/AP

A Kashmiri Muslim woman cries while praying after tying a thread at the shrine of Sufi saint Sheikh Hamzah Makhdoomi in Srinagar, Kashmir. According to belief, Kashmiri Muslims who believe in Sufism -- a mystical form of Islam -- tie ribbons and threads to the gates of shrines to get their needs fulfilled. Fayaz Kabli/Reuters

Cracks where air is leaking are seen on the main exhaust duct of the No.4 reactor at Tokyo Electric Power (TEPCO) Co.'s Fukushima Daini Nuclear Power Station in Fukushima prefecture, Japan, in this handout photo released by TEPCO. Tokyo Electric Power Co/Reuters

A woman walks her dog past a wall near the seafront in Brighton, England. Cathal McNaughton/Reuters

Crystal Johnson, (r.), a supporter of President Obama's healthcare overhaul, argues with a protester outside the 11th Circuit Court of Appeals in Atlanta. A three-judge panel was hearing arguments on whether to reverse a Florida judge's ruling that struck down the law. John Bazemore/AP

People walk in a street blanketed by volcanic ash from Chile's erupting Puyehue-Cordon Caulle volcano in Villa La Angostura in southern Argentina. The Puyehue-Cordon Caulle volcano, dormant for decades, erupted in south-central Chile on Saturday. The wind carried ash across the Andes to Argentina, resulting in the closing of six airports, and dusting this tourist town. DyN/AP

Children dressed in sailor outfits smile before a performance during World Oceans Day celebrations in Taipei, Taiwan. Nicky Loh/Reuters

F-16 fighters of the Thunderbirds, the US Air Force Air Demonstration Squadron, perform during a Romanian-US airshow at Kogalniceanu airport, Romania. Bogdan Cristel/Reuters

A man looks at the work 'Organ Mapping' by Mariechen Danz at the Based in Berlin exhibition in Berlin. The exhibition shows the work of 80 emerging artists who live and work in Berlin. Thomas Peter/Reuters

Noah Badir cools off at a park in Charlotte, N.C. A forecast for a second day of sizzling temperatures in the mid-Atlantic has triggered heat advisories. Chuck Burton/AP

Kamal Jann fixes customers' horse shoes at his stall on a roadside on the outskirts of Islamabad, Pakistan. Muhammed Muheisen/AP

NBC 'Today' show co-hosts Al Roker, Meredith Vieira, Matt Lauer, Ann Curry, and Natalie Morales say goodbye to Meredith on her last day on the show in New York. Peter Kramer/NBC/AP

Britain's general elections used to be straightforward: a predominantly two-horse race between Labour or Conservative governments, left vs. right, red against blue. But as electioneering gets under way for May 7 polls, it's clear the vote has implications for British politics that extend well beyond whoever comes out on top.